onsemi 2N3390

Overview

2N3390 from Fairchild Semiconductor is an NPN general-purpose amplifier transistor designed for low-to-moderate power linear amplification and switching applications up to 300 mA collector current. It features V_CEO = 25 V, I_C = 500 mA (continuous), h_FE = 400–800 at 2 mA/4.5 V, and TO-92 package with emitter-base-collector pinout. It is commonly used in audio preamplifier stages, relay drivers, and signal conditioning circuits.

For engineers reviewing the 2N3390 datasheet, pinout, applications, or equivalent options, key selection considerations include its DC current gain range, thermal resistance (R_θJA = 200 °C/W), noise figure (not specified for 2N3390), maximum junction temperature (150 °C), and compatibility with standard TO-92 PCB footprints.

Technical Context

The 2N3390 operates as a silicon NPN bipolar junction transistor fabricated using Fairchild's Process 10. Its design targets general-purpose analog amplification and digital switching where moderate speed, predictable h_FE, and stable DC biasing are required. It supports continuous collector currents up to 500 mA and withstands V_CEO/V_CBO = 25 V, making it suitable for low-voltage DC-coupled circuits.

Thermal performance is defined by R_θJC = 83.3 °C/W and R_θJA = 200 °C/W, with a maximum junction temperature of +150 °C. The device exhibits small-signal h_fe = 400–1250 at 2 mA/4.5 V/1 kHz, and output capacitance C_ob = 2.0–10 pF at 10 V/1 MHz - parameters confirmed across the 2N3390–2N3393 family.

Key Specifications

Pinout & Package

2N3390 is housed in a standard TO-92 plastic package with molded epoxy body, axial leads, and flat side orientation. Pin identification follows the "B C E" marking sequence visible on the flat side: lead 1 = Base, lead 2 = Collector, lead 3 = Emitter.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose amplifier applications.

Compared with PN2222A and BC547B, the 2N3390 occupies a mid-tier niche: higher gain than PN2222A and higher current capability than BC547B, making it optimal for 12–24 V, 100–300 mA linear or switching roles where both gain and current headroom matter.

Availability

2N3390 is available at Aetrix Electronics and suitable for audio preamplifiers, relay drivers, and sensor signal conditioning circuits requiring stable component supply, consistent parametric binning, and long-term industrial availability.

Supply support for 2N3390 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016. Its legacy discrete portfolio remains widely deployed and supported.

The 2N3390 belongs to Fairchild's legacy NPN general-purpose amplifier family, engineered for cost-sensitive, medium-current linear and switching applications in industrial control, consumer audio, and instrumentation.

FAQ

What is the maximum continuous collector current for the 2N3390?

The 2N3390 has an absolute maximum continuous collector current (I_C) rating of 500 mA at T_A = 25 °C. However, the functional description specifies use up to 300 mA for amplification and switching. Derating is required above 25 °C ambient, at 5.0 mW/°C, to maintain junction temperature ≤150 °C. Always verify thermal design margins when operating near these limits in the 2N3390.

Is the 2N3390 pin-compatible with other transistors in the 2N339x series?

Yes - all variants (2N3390, 2N3391, 2N3391A, 2N3392, 2N3393) share identical TO-92 packaging and pinout: Base–Collector–Emitter (left-to-right, flat side facing). Differences lie solely in h_FE and noise figure bins; the 2N3390 is the highest-gain variant (400–800), making it directly substitutable in footprint-constrained designs where gain is critical.

Does the 2N3390 have a specified noise figure?

No - the published datasheet specifies noise figure (NF = 5.0 dB) only for the 2N3391A variant under defined test conditions (V_CE = 4.5 V, I_C = 100 µA, R_G = 500 Ω, BW = 15.7 kHz). The 2N3390 does not list NF in its electrical characteristics table, and no interpolation or inference to other variants is supported by Fairchild documentation.

What is the thermal resistance from junction to ambient for the 2N3390?

The 2N3390 has a specified R_θJA of 200 °C/W under standard free-air conditions (no heatsink, JEDEC-standard PCB mounting). This value assumes a typical TO-92 mounted on a 1-inch² copper pad. For reliable operation, ensure power dissipation (P_D ≤ 625 mW at 25 °C, derated linearly) stays within thermal limits defined by (T_J − T_A) / R_θJA. The 2N3390's R_θJC is 83.3 °C/W.

Can the 2N3390 be used in switching power supply feedback circuits?

The 2N3390 is not optimized for high-speed switching or precision error amplification in modern SMPS feedback loops. While it can function in discrete linear regulators or low-frequency auxiliary supplies, its h_fe variation, lack of guaranteed slew rate or propagation delay specs, and absence of PSRR characterization make dedicated op-amps or IC comparators preferable. Use the 2N3390 only in non-critical, low-frequency (<10 kHz), or educational feedback paths where its 2N3390 gain and robustness outweigh bandwidth limitations.